Filter inline heater

ABSTRACT

A filter assembly comprising a housing, a filter, a heater, hose fittings, a heat bridge, and insulators. The housing defines interior and exterior regions communicating through apertures. The filter separate the housing into a region upstream of the filter comprising an aperture, and a region downstream of the filter comprising an aperture. The heater extends into the interior region. The hose fittings are each coincident with an aperture and are formed of a material having a high thermal conductivity. The heat bridge is formed of a material having a high thermal conductivity and thermally connects the heater to the hose fittings. The insulators each are formed of a material having a low thermal conductivity, and each at least partially cover a hose fitting.

TECHNICAL FIELD

The present subject matter relates generally to a component of a liquidreducing agent delivery system. More specifically, present subjectmatter relates to heating a filter assembly of a liquid reducing agentdelivery system.

SUMMARY

Provided is a filter assembly comprising a housing, a filter, a heater,hose fittings, a heat bridge, and an insulators. The housing definesinterior and exterior regions communicating through apertures. Thefilter separates the housing into a region upstream of the filtercomprising an aperture, and a region downstream of the filter comprisingan aperture. The heater extends into the interior region. The hosefittings are each coincident with an aperture and are formed of amaterial having a high thermal conductivity. The heat bridge is formedof a material having a high thermal conductivity and thermally connectsthe heater to the hose fittings. The insulators each are formed of amaterial having a low thermal conductivity, and each at least partiallycover a hose fitting.

Also provided is a filter assembly comprising a housing defining aninterior region and exterior region, the interior region and theexterior region being in communication through a first aperture and asecond aperture; a filter adapted for filtering an aqueous ureasolution, the filter within the housing, the filter separating thehousing into an upstream region upstream of the filter, the upstreamregion communicating with the first aperture, and a downstream regiondownstream of the filter, the downstream region communicating with thesecond aperture; a heater extending into the interior region of thehousing; a first hose fitting communicating with the first aperture, thefirst hose fitting formed of a material having a thermal conductivity ofat least 16 W/(m*K); a second hose fitting communicating with the secondaperture, the second hose fitting formed of material having a thermalconductivity of at least 16 W/(m*K); a heat bridge formed of aconductive material having a thermal conductivity of at least 16W/(m*K), thermally connecting the heater to the first hose fitting, andthermally connecting the heater to the second hose fitting; and a firstinsulator formed of a material having a thermal conductivity of at most0.25 W/(m*K), the first insulator at least partially covering the firsthose fitting; and a second insulator formed of a material having athermal conductivity of at most 0.25 W/(m*K), the second insulator atleast partially covering the second hose fitting.

Further provided is a filter assembly for filtering aqueous ureasolution. The filter assembly comprising a housing defining an interiorregion and exterior region, the interior region and the exterior regionbeing in communication through a first aperture and a second aperture.The housing includes a first sub-housing and a second sub-housingreleasably attached to each other by a fastener; a filter adapted forfiltering an aqueous urea solution, the filter received within thehousing, the filter separating the housing into an upstream regionupstream of the filter, the upstream region communicating with the firstaperture, and a downstream region downstream of the filter, thedownstream region communicating with the second aperture; a heatersupported on the second sub-housing and extending into the interiorregion of the housing, wherein the heater is in thermal communicationwith at least the downstream region; a first hose fitting communicatingwith the first aperture; a second hose fitting communicating with thesecond aperture, wherein the first hose fitting and second hose fittingare supported on the second sub-housing; a heat bridge supported on thesecond sub-housing, formed of a conductive material having a thermalconductivity of at least 16 W/(m*K), thermally connecting the heater tothe first hose fitting, and thermally connecting the heater to thesecond hose fitting; and a first insulator formed of a material having athermal conductivity of at most 0.25 W/(m*K), the first insulator atleast partially covering the first hose fitting; and a second insulatorformed of a material having a thermal conductivity of at most 0.25W/(m*K), the second insulator at least partially covering the secondhose fitting.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an sectional elevational view of a first embodiment of afilter inline heater.

FIG. 2 is an sectional elevational view of a first embodiment of afilter inline heater.

FIG. 3 is an sectional elevational view of the first embodiment of afilter inline heater.

FIG. 4 is an sectional elevational view of a second embodiment of afilter inline heater.

DETAILED DESCRIPTION

In some operations, such as, without limitation, over-stoichiometricoperation, internal combustion engines can produce one or more nitrogenoxides as a combustion product. Conversion of nitrous oxide into othercompounds may reduce nitrogen oxide emissions of an internal combustionengine. It is possible to convert nitrogen oxide into nitrogen and waterusing selective catalytic reduction (SCR) technology. In a SCR system,an aqueous urea solution may be used as a reducing agent.

Aqueous urea solution may freeze under certain conditions rendering theaqueous urea solution unable to flow and unable to be used in the SCRsystem. Accordingly, it is desirable to provide a heating system adaptedto deliver heat to one or more components of a SCR system in order tothaw or prevent the freezing of the aqueous urea solution.

Some components of the SCR system may be more difficult to thaw quickly.It remains desirable to provide a heater for the filter assembly of aSCR system that can thaw a desired mass of frozen aqueous urea solutionquickly.

Referring now to FIGS. 1, 2 and 3, shown is a first embodiment of afilter assembly 100. The first embodiment of a filter assembly 100comprises a housing 110, a filter 120, a heater 130, a first hosefitting 140, a second hose fitting 150, a heat bridge 160, a firstinsulator 170, and a second insulator 180. In the non-limiting firstembodiment shown in FIGS. 1, 2 and 3, the filter assembly 100 is adaptedto filter a fluid aqueous urea solution 40. In the non-limiting firstembodiment of a filter assembly 100 shown in FIG. 1, fluid aqueous ureasolution 40 is frozen and is shown as frozen aqueous urea solution 40′.In the non-limiting first embodiment of a filter assembly 100 shown inFIGS. 2 and 3, some of the fluid aqueous urea solution 40 is shown asfluid, and some is frozen and is shown as frozen aqueous urea solution40′.

In FIGS. 1 and 3, the heat bridge 160 is shown in a functional state.For sake of contrast, in FIG. 2, the heat bridge is shown in anon-functional state. The nature of the functionality of the heat bridge160 and the effect on the function of the filter assembly 100 will bediscussed in further detail herebelow.

With continued reference to FIGS. 1, 2 and 3, housing 110 defines aninterior region 114 and exterior region 116. The interior region 114 andexterior region 116 are in communication with one another through afirst aperture 115 and through a second aperture 117. The housing 110may be formed as a single piece or multiple sub-housings or componentsmay be assembled to form housing 110. With continued reference to FIGS.1 and 3, housing 110 may comprise a first sub-housing 111 and a secondsub-housing 112. The first sub-housing 111 and the second sub-housing112 may be attached by a fastener 113. Fastener 113 may be a mechanicalfastener such as a clip, snap fit edge, an external thread 113A andinternal thread 113B formed on opposite sub-housings, as shown, or otherfastener including but not limited to a weld or an adhesive. For exampleand without limitation, in FIGS. 1 and 3, first sub-housing 111 and asecond sub-housing 112 are threadedly engaged by to one another at A byan external thread 113A formed on first sub-housing 111 and an internalthread 113B formed on second sub-housing 112. A seal 119 may beincorporated at or near the joint A of first and second sub-housings111,112 to further form fluid-tight engagement between the sub-housings.For example, an O-ring seal 1A may be provided between first and secondsub-housings 111, 112. It should be understood that there are manyacceptable means to facilitate fluid tight engagement, compressionfitting, welding, soldering, brazing, mechanical fasteners, adhesives,etc., and that threaded engagement and seal is only one such means.

In the non-limiting embodiment shown, first sub-housing includes acup-like member having a base 111A with at least one sidewall 111Bextending axially upward therefrom. The sidewall defines an open end111C opposite base 111A. The cup-like member may have any shape or outercontour. In the non-limiting embodiment shown, the cup-like member has acylindrical sidewall with a circular base. The second sub-housing 112may include a cap with a top wall 112A and a cap sidewall 112B. Capsidewall 112B is located radially inward or outward of sidewall 111Ballowing the sidewalls of first sub-housing 111 and second sub-housing112 to overlap each other to an extent to facilitate attachment. In theexample shown, the cap sidewall 112B is radially outward of sidewall111B defining a cap open end 112C that receives the sidewall 111Btherein. An attachment assembly or fastener 113 extends between theoverlapping portion of sidewall 111B and cap sidewall 112B to attachthem to each other. For example, an internal thread 113B may be formedon the cap sidewall 112B. In the example shown, external thread 113Aextends radially outward from sidewall 111B adjacent to open end 111C offirst subhousing 111 and an internal thread 113B is formed on aninterior surface of cap sidewall 112B of second subhousing 112.

With continued reference to the non-limiting embodiment shown in FIGS.1, 2 and 3, the filter 120 is adapted for filtering fluid aqueous ureasolution 40. The filter 120 may have any shape or configuration suitablefor the filtering application including cyclonic filters, screen filtersor the pleated cylindrical configuration shown. Filter 120 is receivedwithin the housing 110 and may include an end cap or other structuralelement 118 for engagement with a portion of housing. The housing 110may contain one or more interior features adapted to engage othercomponents such as filter 120 for support or location of the filter orto guide flow of fluid aqueous urea solution 40 therethrough. Forexample, a divider, generally indicated by the number 125, may extendinto the housing 110 to engage filter 120. Divider 125 as discussed morecompletely below is used to segregate the flow path into an inletsection and outlet section and defines an inlet flow path and outletflow path relative to filter 120 within housing 110.

With reference to FIGS. 1, 2 and 3, filter 120 has a first side 122 anda second side 124. In the non-limiting embodiment shown in FIGS. 1 and3, the filter 120 separates the interior region 114 of the housing 110into a first region 126, on a first side of the filter 122, and a secondregion 128 on a second side of the filter 124. In the non-limitingembodiment shown in FIGS. 1 and 3, the filter 120 defines asubstantially hollow cylinder with a central bore 120A closed to flow byengagement with a portion of housing 110. For example, upper portion offilter 120 may include a cylindrical cap 118A to close an end of thefilter element and define a central opening into which the filteredfluid is received. Divider 125 includes a cylindrical wall 127 thatengages filter cap 118A to cordon off the bore 120A. An outlet opening115A is provided in divider 125 in registry with first aperture 115 toallow fluid aqueous urea to exit bore 120A. Divider 125 also separatesexterior region 116 radially outward thereof, which is in communicationwith second aperture 117 such that fluid entering the filter 124 entershousing 110 via second aperture 117. In the non-limiting embodimentshown, bore 120A is closed near base 111A of housing 110 by a filterbase 118B to force filtered fluid entering bore 120A through the filtermedium forming the cylindrical wall between cap 118A and base 118B toexit through outlet opening 115A. A seal extending upward from base 111Amay be provided to help close bore 120A. A seal may also be provided onan end of filter 124 to provide the same effect. The interior bore 120Aof the cylinder corresponds to the first region 126, while the exteriorof the cylinder corresponds to the second region 128. The first region126 communicates with the first aperture 115. The second region 128communicates with second aperture 117. Depending on the flow path of thefilter, first region 126 and second region 128 may be upstream ordownstream regions. In the example shown, first region 126 is downstreamof second region 128 (upstream region).

With continued reference to the non-limiting embodiment shown in FIGS.1, 2 and 3, the heater 130 extends into the interior region 114 of thehousing 110. Without limitation, the heater 130 may be an electriccartridge heater having a connector located externally of housing and aheat element extending into heater 130, housing 110. Heat element may belocated at any location internal or external to housing 110 to applyheat to the AUS therein. In the non-limited embodiment shown, heater 130is centrally located within the interior 114 of housing 110. Top wall112A defines a heater opening through which heater 130 extends axiallyinward into housing interior 114 and within bore 120A of filter 120. Adivider 125 is located radially outward of heater 130. The divider 125registers within the bore 120A defining a first region inward thereof incommunication with bore 120A and a second region outward thereof. Theheater 130 is adapted to produce heat energy and impart heat to nearbymaterials and components. In certain non-limiting embodiments, as willbe explained in detail herebelow, the heater 130 is operationallyengaged with one or more components that facilitate heat transfer, oneor more components that impede heat transfer, or both in order totransfer heat to desired materials and components at a desired rate.

With continued reference to the non-limiting embodiment shown in FIGS.1, 2 and 3, a first hose fitting 140 may be coincident with the firstaperture 115. In embodiments in which the first hose fitting 140 iscoincident with the first aperture 115, the fluid communication betweeninterior region 114 and exterior region 116 provided by the firstaperture 115 is provided through the first hose fitting 140. The firsthose fitting 140 may be formed of a solid material that has a highthermal conductivity. Materials that have a high thermal conductivitycomprise those materials that have a thermal conductivity of at least 16W/(m*K). Without limitation, materials that have a thermal conductivityof at least 16 W/(m*K) comprise, aluminum, aluminum nitride, brass,bronze, copper, titanium, zirconium, iron, steel, and stainless steel.The first hose fitting 140 may be formed of a material resistant tocorrosion when directly exposed to aqueous urea solution. Withoutlimitation, materials that are to be considered resistant to corrosionwhen directly exposed to aqueous urea solution are those materials ratedof at least “good” corrosion resistance in the relevant engineeringliterature, for example and without limitation, Corrosion ResistanceTables, Fifth Edition, Part D, pages 3369-3372, by Philip A. Schweitzer,P. E, at the relevant operating temperatures for an SCR system. Withoutlimitation, materials that are to be considered resistant to corrosionwhen directly exposed to aqueous urea solution may include 316 stainlesssteel, 304 stainless steel, titanium, and zirconium.

With continued reference to the non-limiting embodiment shown in FIGS.1, 2 and 3, a second hose fitting 150 may be coincident with the secondaperture 117. In embodiments in which the second hose fitting 150 iscoincident with the second aperture 117, the fluid communication betweeninterior region 114 and exterior region 116 provided by the secondaperture 117 is provided through the second hose fitting 150. The secondhose fitting 150 may be formed of a solid material that has a highthermal conductivity. Materials that have a high thermal conductivitycomprise those materials that have a thermal conductivity of at least 16W/(m*K). Without limitation, materials that have a thermal conductivityof at least 16 W/(m*K) comprise, aluminum, aluminum nitride, brass,bronze, copper, titanium, zirconium, iron, steel, and stainless steel.The second hose fitting 150 may be formed of a material resistant tocorrosion when directly exposed to aqueous urea solution. Withoutlimitation, materials that are to be considered resistant to corrosionwhen directly exposed to aqueous urea solution are those materials ratedof at least “good” corrosion resistance in the relevant engineeringliterature, for example and without limitation, Corrosion ResistanceTables, Fifth Edition, Part D, pages 3369-3372, by Philip A. Schweitzer,P. E, at the relevant operating temperatures for an SCR system. Withoutlimitation, materials that are to be considered resistant to corrosionwhen directly exposed to aqueous urea solution may include 316 stainlesssteel, 304 stainless steel, titanium, and zirconium.

With continued reference to the non-limiting embodiment shown in FIGS.1, 2 and 3, in FIGS. 1 and 3 the heat bridge 160 thermally connects theheater 130 to the first hose fitting 140, and thermally connects theheater 130 to the second hose fitting 150. Thermal connectionfacilitates transfer of heat between the connected components. The heatbridge 160 may be formed of a solid material that has a high thermalconductivity. Materials that have a high thermal conductivity comprisethose materials that have a thermal conductivity of at least 16 W/(m*K).Without limitation, materials that have a thermal conductivity of atleast 16 W/(m*K) comprise, aluminum, aluminum nitride, brass, bronze,copper, titanium, zirconium, iron, steel, and stainless steel. As shownin FIGS. 1 and 3, in certain non-limiting embodiments, portions of theheat bridge 160 may be insulated to prevent heat loss to undesiredcomponents or regions. In the non-limiting embodiment shown in FIGS. 1and 3, the heat bridge is insulated at locations B close to the exteriorregion 116 to prevent heat transferred by the heat bridge 160 from beinglost the exterior region 116. As shown in the non-limiting embodimentshown in FIGS. 1 and 3, the heat bridge 160 may optionally be engaged tothe heater 130 with an optional mechanical fastener 190 adapted tofacilitate transfer of heat between the heater 130 and the heat bridge160. In non-limiting FIG. 2, the heat bridge 160′ is shown, for sake ofcontrast and understanding only, in a non-functional state such thatheat bridge 160′ is shown as not providing thermal connection from theheater 130 to the first hose fitting 140, and not providing thermalconnection from the heater 130 to the second hose fitting 150.

With continued reference to the non-limiting embodiment shown in FIGS.1, 2, and 3, a first insulator 170 at least partially covers the firsthose fitting 140 and insulates the first hose fitting 140 from theexterior region 116 to impede heat transferred to the first hose fitting140 being lost the exterior region 116. In certain non-limitingembodiments, as shown in FIGS. 1 and 3, the heat bridge 160 and thefirst hose fitting 140 may both be in thermal engagement and both may beinsulated from the exterior region 116 by first insulator 170. The firstinsulator 170 may be formed of a solid material that has a low thermalconductivity. Materials that have a low thermal conductivity comprisethose materials that have a thermal conductivity of no more than 0.25W/(m*K). Without limitation, materials that have a thermal conductivityof no more than 0.25 W/(m*K) comprise, nylon 6 and acrylic glass.

With continued reference to the non-limiting embodiment shown in FIGS.1, 2, and 3, a second insulator 180 at least partially covers the secondhose fitting 150 and insulates the second hose fitting 150 from theexterior region 116 to prevent heat transferred to the second hosefitting 150 from being lost the exterior region 116. In certainnon-limiting embodiments, as shown in FIGS. 1 and 3, the heat bridge 160and the second hose fitting 150 may both be in thermal engagement andboth may be insulated from the exterior region 116 by second insulator180. The second insulator 180 may be formed of a solid material that hasa low thermal conductivity. Materials that have a low thermalconductivity comprise those materials that have a thermal conductivityof no more than 0.25 W/(m*K). Without limitation, materials that have athermal conductivity of no more than 0.25 W/(m*K) comprise, nylon 6 andacrylic glass. In some embodiments the second insulator 180 and thefirst insulator 170 may be formed of the same unitary component.

With continued reference to the non-limiting embodiment shown in FIGS.1, 2, and 3, in certain embodiments, and without limitation, there is adefined or pre-determined direction of flow for fluid aqueous ureasolution 40 through filter assembly 100 such that there is an upstreamdirection and downstream direction through filter assembly 100 whereinfluid aqueous urea solution 40 flows from the upstream direction to thedownstream direction and from an upstream region to a downstream region.In such embodiments, it should be understood that the first region 126may be identified as a downstream region downstream of the filter 120and that the second region 128 may be identified as an upstream regionupstream of the filter 120.

In the desired operation of the non-limiting embodiment shown in FIGS.1, 2 and 3, fluid aqueous urea solution 40 flows into housing 110 byentering second aperture 117; flows through second hose fitting 150 intothe second region 128 outside filter 120; flows across the filter 120from second side 124 to first side 122 and into first region 126; flowsthrough first hose fitting 140 and flows out of housing 110 by exitingfirst aperture 115.

Under some conditions the fluid aqueous urea solution 40 in the filterassembly 100 can freeze. For example, in some embodiments, the fluidaqueous urea solution 40 is a formulations that freezes at −11Centigrade. Fluid aqueous urea solution 40 can freeze into frozenaqueous urea solution 40′ if exposed to temperatures at or below at −11Centigrade. When it becomes desirable to operate the filter assembly100, with frozen aqueous urea solution 40′ therein, the frozen aqueousurea solution 40′ can impede or entirely prevent desired flow throughthe filter assembly 100. Accordingly, it is desirable under suchconditions to thaw the frozen aqueous urea solution 40′ in the filterassembly 100 quickly. It should be understood that some regions of thefilter assembly 100 are more critical to flow than are other regions.For example and without limitation, in the embodiment shown in FIG. 1,the frozen aqueous urea solution 40′ is entirely frozen throughout thefilter assembly 100. Flow of frozen aqueous urea solution 40′ throughthe filter assembly 100 in the embodiment shown in FIG. 1, is notpossible. By way of further example and without limitation, in theembodiment shown in FIG. 2, the heater 130 is operated to thaw thefrozen aqueous urea solution 40′. As noted above, the embodiment in FIG.2 is shown with a non-operative heat bridge 160′. Accordingly the heat Hgenerated by heater 130 first affects and thaws the frozen aqueous ureasolution 40′ closest to heater 130. The result is that, at least in thevery near term following initiation of heating, there is fluid aqueousurea solution 40 in the filter assembly 100 near the heater 130 that hasthawed, but the fluid aqueous urea solution 40 cannot flow through thefilter assembly because regions necessary to flow, such as, withoutlimitation, first hose fitting 140 and second hose fitting 150, arestill occluded by frozen aqueous urea solution 40′, which has yet tothaw due to it being distal from the heater 130. In the contrastingembodiment shown in FIG. 3, the heat bridge 160 is functional.Accordingly, in FIG. 3, some of the heat H generated by heater 130 flowsthrough the heat bridge 160, into the thermally connected first hosefitting 140, into the thermally connected second hose fitting 150, andfrom each hose fitting 140, 150 into the frozen aqueous urea solution40′ therein to thaw it. As some of the heat H from the heater affectsand thaws the frozen aqueous urea solution 40′ closest to heater 130,some portion of the heat H from heater 130 is also thawing the frozenaqueous urea solution 40′ in the hose fittings 140, 150. The result isthat, at least in the very near term following initiation of heating,there is fluid aqueous urea solution 40 in the filter assembly 100, thatcan flow through the filter assembly 100 because regions necessary toflow, such as, without limitation, the regions within first hose fitting140 and second hose fitting 150, are also thawed.

Referring now to FIG. 4, shown is a second embodiment of a filterassembly 200. The first embodiment of a filter assembly 200 comprises ahousing 210, a filter 220, a heater 230, a first hose fitting 240, asecond hose fitting 250, a heat bridge 260, a first insulator 270, and asecond insulator 280. In the non-limiting second embodiment shown inFIG. 4, the filter assembly 200 is adapted to filter a fluid aqueousurea solution, schematically shown at 40.

With continued reference to FIG. 4, housing 210 defines an interiorregion 214 and exterior region 216. The interior region 214 and exteriorregion 216 are in communication with one another through a firstaperture 215 and through a second aperture 217. The housing 210 may beformed as a single piece or multiple sub-housings or components may beassembled to form housing 210. With continued reference to FIG. 4,housing 210 may comprise a first sub-housing 211 and a secondsub-housing 212. The first sub-housing 211 and the second sub-housing212 may each comprise one or more engagement components 213 tofacilitate fluid tight engagement to one or more other components. Forexample and without limitation, in FIG. 4, first sub-housing 211 and asecond sub-housing 212 are threadedly engaged by fastener 213 to oneanother at A. Fastener 213 may be any suitable fastener as discussed inthe earlier embodiment including the threaded fastener shown. It shouldbe understood that other fasteners may include, but are not limited to,a compression fitting, welding, soldering, brazing, mechanicalfasteners, adhesives, etc., and that threaded engagement is only oneacceptable fastening means. The housing 210 may contain one or moreinterior features 218 adapted to engage other components, or guide flowof fluid aqueous urea solution 40 therethrough. In the embodiment shown,interior feature 218 includes a divider 225 that extends axially inwardfrom second sub-housing 212. Divider 225 is sized to fit within the bore220A defined by filter 220 to separate the interior region 214 fromexterior region 216. Interior feature 218 may also include a support 229that extends axially inward from an opposite end of housing to support abase of filter 220. In the example shown, support 229 is a cylindricalplug that extends axially inward from first sub-housing 211 at leastpartially into bore 220A opposite divider 225 to close the bore 220A ateach end.

With continued reference to the non-limiting embodiment shown in FIG. 4,the filter 220 is adapted for filtering fluid aqueous urea solution 40.The filter 220 is supported within the housing 210. The filter 220 has afirst side 222 and a second side 224. In the non-limiting embodimentshown in FIG. 4, the filter 220 separates the interior region 214 of thehousing 210 into a first region 226, on a first side of the filter 220,and a second region 228 on a second side 224 of the filter 220. In thenon-limiting embodiment shown in FIG. 4, the filter 220 defines asubstantially hollow cylinder with the bottom closed to flow byengagement with support 229 of housing 210, the top and interior of thecylinder corresponds to the first region 226, while the exterior of thecylinder corresponds to the second region 228. The first region 226comprises first aperture 215. The second region 228 comprises secondaperture 217.

With continued reference to the non-limiting embodiment shown in FIG. 4,the heater 230 extends into the interior region 214 of the housing 210.Without limitation, the heater 230 may be an electric cartridge heater.The heater 230 is adapted to produce heat energy and impart heat tonearby materials and components. In certain non-limiting embodiments, aswill be explained in detail herebelow, the heater 230 is operationallyengaged with one or more components that facilitate heat transfer, oneor more components that impede heat transfer, or both in order totransfer heat to desired materials and components at a desired rate.

With continued reference to the non-limiting embodiment shown in FIG. 4,a first hose fitting 240 may be coincident with the first aperture 215.In embodiments in which the first hose fitting 240 is coincident withthe first aperture 215, the fluid communication between interior region214 and exterior region 216 provided by the first aperture 215 isprovided through the first hose fitting 240. The first hose fitting 240may be formed of a solid material that has a high thermal conductivity.The first hose fitting 240 may be formed of a material resistant tocorrosion when directly exposed to aqueous urea solution.

With continued reference to the non-limiting embodiment shown in FIG. 4,a second hose fitting 250 may be coincident with the second aperture217. In embodiments in which the second hose fitting 250 is coincidentwith the second aperture 217, the fluid communication between interiorregion 214 and exterior region 216 provided by the second aperture 217is provided through the second hose fitting 250. The second hose fitting250 may be formed of a solid material that has a high thermalconductivity. The second hose fitting 250 may be formed of a materialresistant to corrosion when directly exposed to aqueous urea solution.

It is to be understood that the term “hose fitting” is not intended tobe limited to components adapted to provide engagement adapted for fluidcommunication to associated hoses in particular, but to extend toassociated pipes, associated ducts, and other sorts of associatedconduits generally. Moreover, the hose fittings 140, 150, 240, 250 mayeach be engaged with an associated conduit by any means chosen with goodengineering judgment including, but not limited to, threaded engagement,a hose barb, a mechanical fastener, a clamp, an adhesive, welding,brazing, soldering, or some combination thereof.

With continued reference to the non-limiting embodiment shown in FIG. 4,the heat bridge 260 thermally connects the heater 230 to the first hosefitting 240, and thermally connects the heater 230 to the second hosefitting 250. Thermal connection facilitates transfer of heat between theconnected components. The heat bridge 260 may be formed of a solidmaterial that has a high thermal conductivity. As shown in FIG. 4, incertain non-limiting embodiments, portions of the heat bridge 260 may beinsulated to prevent heat loss to undesired components or regions. Inthe non-limiting embodiment shown in FIG. 4, the heat bridge isinsulated at locations B close to the exterior region 216 to preventheat transferred by the heat bridge 260 from being lost the exteriorregion 216. As shown in the non-limiting embodiment shown in FIG. 4, theheat bridge 260 may optionally be engaged with the heater 230 throughbeing unitarily formed or cast therewith. As shown in the non-limitingembodiment shown in FIG. 4, the heat bridge 260 may optionally bethermally engaged to one or both of the hose fittings 240, 250 bythreaded engagement. As shown in the non-limiting embodiment shown inFIG. 4, the heat bridge comprises female threaded holes into which malethreaded fittings may be threadedly engaged to provide the desiredthermal connection. Similar to the above explanation regardingengagement with respect to the housing, it should be understood thatthere are many acceptable means to facilitate thermal engagement,compression fitting, welding, soldering, brazing, mechanical fasteners,adhesives, etc., and that threaded engagement is only one such means.

With continued reference to the non-limiting embodiment shown in FIG. 4,a first insulator 270 at least partially covers the first hose fitting240 and insulates the first hose fitting 240 from the exterior region216 to impede heat transferred to the first hose fitting 240 being lostthe exterior region 216. In certain non-limiting embodiments, as shownin FIG. 4, the heat bridge 260 and the first hose fitting 240 may bothbe in thermal engagement and both may be insulated from the exteriorregion 216 by first insulator 270. The first insulator 270 may be formedof a solid material that has a low thermal conductivity.

With continued reference to the non-limiting embodiment shown in FIG. 4,a second insulator 280 at least partially covers the second hose fitting250 and insulates the second hose fitting 250 from the exterior region216 to impede heat transferred to the second hose fitting 250 being lostthe exterior region 216. In certain non-limiting embodiments, as shownin FIG. 4, the heat bridge 260 and the second hose fitting 250 may bothbe in thermal engagement and both may be insulated from the exteriorregion 216 by second insulator 280. The second insulator 280 may beformed of a solid material that has a low thermal conductivity.

With continued reference to the non-limiting embodiment shown in FIG. 4,in certain embodiments, and without limitation, there is a defined orpre-determined direction of flow for fluid aqueous urea solution 40through filter assembly 200 such that there is an upstream direction anddownstream direction through filter assembly 200 wherein fluid aqueousurea solution 40 flows from the upstream direction to the downstreamdirection and from an upstream region to a downstream region. In suchembodiments, it should be understood that the first region 226 may beidentified as a downstream region downstream of the filter 220 and thatthe second region 228 may be identified as an upstream region upstreamof the filter 220.

In the desired operation of the non-limiting embodiment shown in FIG. 4,fluid aqueous urea solution 40 flows into housing 210 by entering secondaperture 217; flows through second hose fitting 250 into the secondregion 228 outside of filter 220; flows across the filter 220 fromsecond side 224 to first side 222 and into first region 226; flowsthrough first hose fitting 240 and flows out of housing 210 by exitingfirst aperture 215.

Under some conditions the fluid aqueous urea solution 40 in the filterassembly 200 can freeze. For example, in some embodiments, the fluidaqueous urea solution 40 is a formulations that freezes at −11Centigrade. Fluid aqueous urea solution 40 can freeze into frozenaqueous urea solution 40′ if exposed to temperatures at or below at −11Centigrade. When it becomes desirable to operate the filter assembly 200with frozen aqueous urea solution 40′ therein, the frozen aqueous ureasolution 40′ can impede or entirely prevent desired flow through thefilter assembly 200. Accordingly, it is desirable under such conditionsto thaw the frozen aqueous urea solution 40′ in the filter assembly 200quickly. For example and without limitation, in the embodiment shown inFIG. 4, some of the heat H generated by heater 230 flows through theheat bridge 260, into the thermally connected first hose fitting 240,into the thermally connected second hose fitting 250, and from each hosefitting 240, 250 into the frozen aqueous urea solution 40′ therein tothaw it. As some of the heat H from the heater affects and thaws thefrozen aqueous urea solution 40′ closest to heater 230, some portion ofthe heat H from heater 230 is also thawing the frozen aqueous ureasolution 40′ in the hose fittings 240, 250. The result is that, at leastin the very near term following initiation of heating, there is fluidaqueous urea solution 40 in the filter assembly 200, that can flowthrough the filter assembly 200 because regions necessary to flow, suchas, without limitation, the regions within first hose fitting 240 andsecond hose fitting 250, are also thawed.

While the subject matter has been described with reference to certainembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the scope of the subject matter. In addition, manymodifications may be made to adapt a particular situation or material tothe teachings of the subject matter without departing from its scope.Therefore, it is intended that the subject matter not be limited to theparticular embodiment disclosed, but that the subject matter willinclude all embodiments falling within the scope of the appended claims.

1.-20. (canceled)
 21. A filter assembly comprising: a housing comprisingan interior and exterior, the interior and the exterior in fluidcommunication through a first aperture and a second aperture; a filtercapable of filtering an aqueous solution, the filter positioned withinthe housing, the filter separating the housing into: a first regionupstream of the filter, the first region in fluid communication with thesecond aperture, and a second region downstream of the filter, thesecond region in fluid communication with the first aperture; a heaterextending into the interior of the housing; a first hose fittingextending into the housing and in fluid communication with the firstaperture, a second hose fitting extending into the housing and in fluidcommunication with the second aperture; and a heat bridge thermallycoupling the heater to the first hose fitting and to the second hosefitting.
 22. The filter assembly of claim 21, wherein a portion of thehousing comprises an insulating material.
 23. The filter assembly ofclaim 22, wherein the first hose fitting is formed of a materialselected from the group consisting of: stainless steel, titanium, andzirconium.
 24. The filter assembly of claim 22, wherein the second hosefitting is formed of a material selected from the group consisting of:stainless steel, titanium, and zirconium.
 25. The filter assembly ofclaim 22, wherein the heat bridge is formed of a material selected fromthe group consisting of: aluminum, aluminum nitride, brass, bronze,copper, titanium, zirconium, iron, steel, and stainless steel.
 26. Thefilter assembly of claim 21 wherein, the housing comprises a firstportion and a second portion, wherein the first portion of the housingcomprises a cap.
 27. The filter assembly of claim 26, wherein the cap isin threaded engagement with the second portion of the housing.
 28. Thefilter assembly of claim 26, wherein, the heat bridge is at leastpartially insulated from the exterior of the housing by the firstportion of the housing.
 29. The filter assembly of claim 26 wherein thefirst portion of the housing is formed of a material having a thermalconductivity of at most 0.25 W/(m*K).
 30. The filter assembly of claim21, wherein the first and second hose fittings have a thermalconductivity of at least 16 W/(m*K).
 31. The filter assembly of claim 21wherein the heat bridge has a thermal conductivity of at least 16W/(m*K).
 32. The filter assembly of claim 21, wherein, the insulatingmaterial comprises nylon.
 33. The filter assembly of claim 21, whereinthe filter defines a substantially hollow cylinder and the heaterextends into an interior volume of the cylinder.
 34. The filter assemblyof claim 21, wherein the first hose fitting and second hose fittingextend radially outward from their respective first aperture and secondaperture, wherein the heating element is located between the firstaperture and second aperture, wherein the heat bridge extends radiallyoutward from the heat element to thermally connect the heater to thefirst hose fitting and second hose fitting.
 35. The filter assembly ofclaim 31, wherein the filter defines a central bore, the second regionbeing within the central bore, the second aperture being locatedradially outward of the filter, a divider extending axially inward fromthe cap, the divider registering with an interior surface of the filterto fluidly separate the first region from the second region, wherein theheater extends axially inward from the cap radially inward of thedivider, the heater extending into the central bore.
 36. The filterassembly of claim 26, wherein the second portion of the housing includesa cup-shaped structure having a base with at least one sidewallextending axially upward from the base, the sidewall defining an openend opposite the base, wherein the filter is received in the cup-shapedstructure, and the first portion of the housing comprises a capattachable to the cup-shaped structure, the cap closing the open end;wherein the heater, first hose fitting and second hose fitting aresupported on the cap; wherein the first aperture and second aperture areformed in the cap.
 37. The filter assembly of claim 36, wherein the capincludes a top wall and a cap sidewall extending axially downward fromthe top wall, the cap sidewall being located radially outward of thesidewall of the cup-shaped member, an attachment assembly connecting thecap sidewall and the sidewall of the cup-shaped member, the attachmentassembly being located therebetween.
 38. The filter assembly of claim37, wherein the attachment assembly includes an external threadextending radially outward from the sidewall of the cup-shaped memberand an internal thread defined in the cap sidewall.
 39. A filterassembly for filtering aqueous urea solution, the filter assemblycomprising: a housing defining a pair of regions in fluid communicationthrough a first aperture and a second aperture, wherein a portion of thehousing comprises one or more insulating materials; a filter receivedwithin the housing, the filter separating the housing into a firstregion upstream of the filter, the first region in fluid communicationwith the second aperture, and a second region downstream of the filter,the second region in fluid communication with the first aperture; aheater extending into a first of the pair of regions of the housing,wherein the heater is in thermal communication with at least a second ofthe pair of regions; a first hose fitting in fluid communication withthe first aperture; and a second hose fitting in fluid communicationwith the second aperture.
 40. The filter assembly of claim 39, whereinthe first hose fitting and second hose fitting are supported on thefirst of the pair of regions of the housing and are formed of a materialselected from the group consisting of stainless steel, titanium andzirconium.
 41. The filter assembly of claim 40 further comprising a heatbridge supported on the heater, the heat bridge being formed of amaterial selected from the group consisting of aluminum, aluminumnitride, brass, bronze, copper, titanium, zirconium, iron, steel, andstainless steel, thermally connecting the heater to the first hosefitting and to the second hose fitting.
 42. The filter assembly of claim41, wherein the filter defines a central bore and the housing includes adivider extending into the central bore to separate the first regionfrom the second region, the divider including an opening that fluidlycommunicates with the first hose fitting, and wherein the second hosefitting fluidly communicates with the first region radially outward ofthe divider.
 42. The filter assembly of claim 42 further comprising asupport at an opposite end of the housing relative to the divider,wherein the support extends at least partially into the central bore.44. The filter assembly of claim 43, wherein the heat bridge includes aportion to which the first hose connector and second hose connector areattached.
 45. The filter assembly of claim 44, wherein the heat bridgehas a thermal conductivity of at least 16 W/(m*K).